1. Field of the Invention
This invention relates to a medical vascular guide wire for aiding the insertion of a catheter into, particularly, blood vessels of the living body for withdrawal of blood and other specimens from the affected parts, or for infusion of a drug solution to the affected parts. It also relates to a self-guiding type catheter, namely, a catheter capable of guiding its tip to the peripheral blood vessels in the affected parts.
2. Description of the Prior Art
Most conventional guide wires are coil-form metal wires supplied by, for example, COOK Inc., Universal Medical Instrument Corp. and USCI, a division of C. R. Bard, Inc. These coiled metal wires have some disadvantages. Namely, first, the coiled metal wires possess an uneven surface, and hence, thrombi are liable to be deposited thereon. Secondly, the metal wires are too rigid to permit their tips to reach the blood vessels in the affected parts without causing undue strain or pain to the patient, or taking a great deal of time. Thirdly, the coiled metal wires are not easy to manipulate so that their tips will reach the affected parts. Fourthly, there is a danger that the coiled metal wires may injure the intimae of blood vessels.
Most conventional catheters are made of synthetic resin tubes and supplied by, for example, Universal Medical Instrument Corp., Electro-Catheter Corp. and USCI, a division of C. R. Bard, Inc. These catheters are used in combination with the aforesaid metal guide wires. These catheters also have some disadvantages. That is first, the catheters are larger in diameter than the guide wires, and, therefore, it is difficult for the catheter tip to reach the intended location, particularly in peripheral blood vessels, where the guide wire has reached. Furthermore, it is generally difficult to accomplish the catheterization without causing undue strain or pain to the patient. Secondly, in the process of catheterization, many kinds of catheters and guide wires must be used in combination. Thus, the procedure requires a substantially long period of time.